Background: The occurrence of brain metastases is an emerging problem in patients with metastatic breast cancer. In the present study, we looked at risk factors for brain metastasis among patients with metastatic breast cancer.
Patients and methods: The risk factors for brain metastasis were first determined in a series of 215 patients with metastatic breast cancer. Risk factors identified in the multivariate analysis were re-evaluated in a confirmatory series of 199 patients with metastatic breast cancer. All the patients had been included in prospective randomized trials that evaluated chemotherapy or endocrine therapy in an adjuvant setting.
Results: In the first series, the presence of lung metastases (hazard ratio = 4.3, 95% CI: 1.9-9.3, P=0.0003) and negative hormone receptor status (hazard ratio = 4.2, 95% CI: 1.7-11, P=0.002) were the only predictive factors associated with the occurrence of brain metastases in the multivariate analysis. The second series confirmed that the presence of lung metastases and negative hormone receptor status were associated with the occurrence of brain metastases.
Conclusion: The presence of lung metastases as the first site of relapse and a negative hormone receptor status are predictive for the occurrence of brain metastases in patients with metastatic breast cancer. A prophylactic treatment should be evaluated in these subsets of patients.